Point-of-care testing with CRP in primary care: a registry-based observational study from Norway.

BACKGROUND: Norwegian primary health care is maintained on the regular general practitioners (RGPs), GP's contracted to the municipalities in a list patient system, working at daytime and at out-of-hours services (OOH services). Respiratory disease is most prevalent during OOH services, and in more than 50 % of the consultations, a CRP test is performed. Children in particular have a high consultation rate, and the CRP test is frequently conducted, but the contributing factors behind its frequent use are not known. This study compares the RGPs rate of CRP use at daytime and OOH in consultations with children and how this rate is influenced by characteristics of the RGPs. METHODS: A cross-sectional register study was conducted based on all (N = 2,552,600) electronic compensation claims from consultations with children ≤ 5 year during the period 2009-2011 from primary health care. Consultation rates and CRP use were estimated and analysed using descriptive methods. Being among the 20% of RGPs with the highest rate of CRP use at daytime or OOH was an outcome measure in regression analyses using RGP-, and RGP list characteristics as explanatory variables. RESULTS: One third of all RGPs work regularly in OOH services, and they use CRP 1.42 times more frequently in consultations with children in OOH services than in daytime services even when the distribution of diagnosis according to ICPC-2 chapters is similar. Not being approved specialist, have a large number at their patient-lists but relatively few children on their list and a large number of consultations with children were significantly associated with frequent use of CRP in daytime services. The predictors for frequent CRP use in OOH services were being a young doctor, having many consultations with children during OOH and a frequent use of CRP in daytime services. CONCLUSIONS: The increase in the frequency of CRP test use from daytime to OOH occurs in general for RGPs and for all most used diagnoses. The RGPs who use the CRP test most frequently in their daytime practice have the highest rate of CRP in OOH services.